Recoilless rifle firing mechanism



1964 w. B. STAPP ETAL 3,144;808

RECOILLESS RIFLE FiRING MECHANISM Filed Sept. 11, 1962 V 3 Sheets-Sheet 1 INVENTORS- WALTER B. STAPP FRANCIS W. DIETSCH 1 11; QJQhMWJM ATTORNEY Aug- 96 vw. B. STAPP ETAL 3, 4,808

- RECOILLESS RIFLE FIRING MECHANISM Filed Sept. 11, 19 62 5 Sheets-Sheet 2 to Q 1 I m p a? u IO (0 IO/w bs 0 'I 28 LE A! Q Q m no 2: m a (3 g u 0k 8 N) a Q .2 N w 3'- g g 0 g 8 F 8 m INVENTORS. a n WALTER B. STAPP I FRANCIS W. DIETSCH m t (329m BY W n 3 S m ATTORNEY Aug. 18, 1964 w. B. STAPP ETAL 3,

RECOILLESS RIFLE FIRING MECHANISM Filed Sept. 11, 1962 5 Sheets-Sheet 3 INVENTORS. WALT ER B. STAPP F'RANCIS W. DI ETSCH ATTORNEY 3/. mm; 41 3 W United States Patent Ofi 3,144,858 Patented Aug. 18, 1964 ice 3,144,808 RECOILLESS RIFLE FIRING MECHANISM Walter B. Stapp, Fair Oaks, Calif., and Francis W. Dietsch, Levittown, Pa., assignors to the United States of America as represented by the Secretary of the Army Filed Sept. 11, 1962, Ser. No. 222,977 Claims. (6]. 89--1.7)

This invention relates to manually portable recoilless rifles which function to fire a fin stabilized projectile while resting on either the shoulder of the gunner or on a monopod-bipod support. More particularly, the invention relates to a firing mechanism which greatly simplifies and facilitates the operation of such rifles.

Heretofore, various types of firing mechanism have been devised for recoilless rifles. Many of these mechanisms are highly complicated. This results largely from the fact that they rely on rotation of the nozzle to disengage it from the breech end of the barrel. A further difficulty is the number of parts utilized to perform the various functions of the mechanism. The present invention avoids these difficulties by the provision of a nozzle which is clamped to the breech end of the barrel by a lock ring. A control lever functions to release the nozzle and lock ring from the barrel and is automatically locked against rotation during opening and closing of the nozzle. When the nozzle is closed, the lever is automatically released for a limited rotation whereby the nozzle is clamped to the barrel. During this limited rotation the lever also rotates a cocking shaft whereby a hammer is cocked and a scar or actuator is positioned between the cocked hammer and a catch which is released by the pulling of a firing cable.

The invention will be better understood from the following description when considered in connection with the accompanying drawings and its scope is indicated by the appended claims.

Referring to the drawings:

FIGS. 1 and 2 illustrate the rifle as viewed from its right and left sides,

FIG. 3 is a generally horizontal section through the bar breech closure across the nozzle in FIG. 2 and indicating the relation between the various parts of the rifies operating mechanism,

FIG. 4 is an exploded view of the parts which constitute the breech group of the gun,

FIG. 5 illustrates the cocking mechanism of the gun, and

FIG. 6 shows a detail of the cocking shaft which forms a part of the cooking mecahnism.

As indicated by FIGS. 1 and 2, the gun includes a barrel it), a sight monopod 11 and a bipod 12 which may be folded forward against the barrel so as to function as a shoulder rest when the gun is carried. It also includes a trigger 13 well forward of the breech. All these features are well known and form no essential part of the present invention which relates more particularly to the gun operating mechanism.

This mechanism includes a bar type breech block and nozzle member 14 which is rotatable about a pivot pin 15 (FIG. 3) by means of a handle 16. The handle 16 is key attached to the end of a cocking shaft 17 and has at its breech end an external recess 18 (FIGS 4 and 5) and an internal recess 19 (FIG. 4). The internal recess 19 receives within it and cooperates with a stop 29 (FIGS. 3 and 4) to limit the rotation of the handle 16 and shaft 17 The stop 20 is fixed to the nozzle member 14. The external slot 18 receives within it and cooperates with a pin 21 which extends outwardly from a lock ring 22. The cocking shaft 17 has at its lower end a groove 23 and at the other end a key 24. In assembling the handle 16, the

key 24 is passed through a cocking shaft positioning plate 25 into a keyway 24a in the hub of the handle (FIG. 4).

The lock ring 22 (FIGS. 3 and 4) has an interrupted thread 26 which cooperates with a mating internal interrupted thread 26a on the breech end of the barrel 10. The lock ring 22 is partially threaded onto the forward end of the nozzle 14 by means of threads 27 and 28. With this arrangement, rotation of the handle 16 in one direction functions through the external groove 18 and the pin 21 to rotate the lock ring relative to both the barrel and nozzle and thus disengage the interrupted threads 26 of the lock ring from the interrupted threads 26a of the barrel so that the nozzle 14 with ring 22 may be swung open wide enough about its hinge pin 15 to permit the insertion of a cartridge into the barrel 10. Rotation of the handle 16 in the opposite direction functions through the same external recess or groove 18 and pin 21 to re-engage the interrupted threads of the lock ring and barrel and to tighten the breech block and nozzle member 14 against the breech of the barrel. At the ends of its travel, the handle 16 is locked in position by a pin 29.

Mounted in the bar breech of nozzle 14 as shown in FIGS. 1 and 2 is a hammer 30 which has a firing pin 31 (FiG. 3) at its inner end, has an aperture 32 through which the cocking shaft 17 extends and is biased against the cooking shaft by a spring 33. From FIGS. 3, 4 and 5 it can be seen that the cocking shaft 17 has a section 34 cut away so that rotation of the shaft provides for cocking and firing of the hammer 30.

In addition to serving as the pivot of the handle 16 and retracting the hammer 31), the cocking shaft 17 performs two additional functions. It positions a hammer actuator or sear 35 and when rotated to a predetermined position it cooperates with a latch 36 to prevent the handle 16 and shaft 17 from rotating when the breech block 14 is open or hinged away from the barrel.

One end of the actuator or sear 35 is adapted to engage a notch in the hammer 30 (FIG. 3). The other end of the actuator 35 engages a catch 48 (FIGS. 3 and 5). Midway between its ends the actuator has a cutaway section 37 which cooperates with a cam surface 38 near the lower end of the cocking shaft 17 (FIGS. 4 and 5). As the shaft 17 is rotated, the cam surface 38 engages the end wall 38a of the slot 37 and raises the actuator 35 to its cocked position as shown in FIG. 3. The catch 48, at its forward end, engages a fitting 39 (FIG. 3) which is fixed to a firing cable 40.

Assuming the breech block 14 and the lock ring 22 to be in their fully locked positions, the gun is fired by pulling the cable 40, thus disengaging the catch 48 from the actuator 35 and allowing the spring 33 to actuate the hammer 30 moving firing pin 31 forward. When the lock ring 22 is out of its fully closed position, a scar or actuator lock 41 prevents movement of the catch 48 and fitting 39. This follows from the fact that the sear lock 41 now engages a rear surface of the lock ring 22 and precludes firing of the gun when the breech block and lock ring are in any position other than their fully closed positions.

As the breech block 14 and its associated parts are moved away from their fully closed positions, the clevis 66 carried thereby functions through a link 42 and an extractor lever 43 to actuate an extractor 44, the lever 43 being biased to its illustrated position by a leaf spring 45 (FIG. 3).

The latch 36 extends down through the catch 48 and plate 47 and has at its lower end a lateral extension 49 which engages a tang 50 in stationary hinge block 51 (FIG. 3). The extension 49 is biased into engagement with the tang 50 by a spring 52 extending between the sear lock 41 and the head 53 of the latch 36. The head 53 is provided with a portion shaped to fit into the groove 23 at the lower end of the cocking shaft 17 when the shaft is rotated to a predetermined position. As shown in FIG. 6, the groove 23 has an axial extension 46. The relation between the latch 36, the tang 50 and the groove 23 is such that (1) the cocking shaft 17 is locked against rotation while the nozzle 14, and lock ring 22 are in a position other than fully closed, and (2) the cocking shaft 17 is released to unlock the handle 16 for rotation of the lock ring to clamp the nozzle to the barrel, this release being effected 'by disengagement of the head 53 from the groove 23.

The firing cable 40 extends through a sheath 54 and a lock 55 to a lever 56 which is pivoted about a pin 57. At the end of the cable are a nut 58 and a plurality of washers 59. Associated with the lever 56 are (1) the trigger 13 which is pivoted at 60, (2) a safety 61 which is pivoted at 62 and is attached to the trigger 13 by a spring 63, and (3) a grip 64. This is a conventional type of trigger mechanism. As is well understood by those skilled in the art it is so adjusted that it can fire the gun only when the safety and trigger are pressed simultaneously.

As previously indicated, firing of the gun leaves the actuator 35 disengaged from the hammer 3t), and the latch 36 disengaged from the cooking shaft 17. Subsequent operation of the gun involves rotation of the handle 16 through an angle determined by the relation between the pin 21 on the ring 22 and the internal recess 19 on the hub of the handle. During this rotation of the handle 16 and cocking shaft 17, the interrupted thread 26 of the ring 22 is disengaged from the interrupted thread of the barrel 10. At the same time, the cocking shaft 17 is so related to the hammer 30 and the sear 35 that the spring 33 is not compressed and the sear is disengaged from the hammer 30.

As the nozzle and lock ring start to swing about the hinge 15, the spring 52 forces the latch 36 into the groove 23 thereby locking the cocking pin 17 against rotation when the breech assembly is moved from its closed position.

As the breech 14 rotates about the pin 15, a clevis 66 also rotates. Rotation of the clevis 66 functions through the link 42 and extractor actuator 43 to actuate the ex tractor 44. Clevis 66 also positions a loaders safety 65 into its safe position. Upon loading the round, the extractor 44 returns to normal position by overriding the extractor actuator 43, this being effected by means of the elongated hole 67 in the extractor actuator.

When the nozzle reaches its closed position, catch 48 is re-engaged with the sear 35 and the latch 36 disengaged from the cocking shaft 17 and the handle 16 is freed and rotated to engage the interrupted threads 26, 26a and to clamp the nozzle to the barrel. At the same time the shaft 17 is rotated to return the cam 38 to its inactive position. As previously indicated, the hammer is actuated by pulling the catch 48 away from the lower end of the sear.

The gun is designed to fire a fin stabilized round. When the primer moves down the barrel within the tail section of the fin stabilized round, the firing pin 31 is exposed to direct chamber pressure. This pressure moves the firing pin rearward and effects a seal which prevents combustion products from entering the space containing the firing mechanism. The spring 45 keeps the link 43 in engagement with theextractor 44 and acts as the return force for the link mechanism when the extractor is over powered into the home position by the seating of the round of ammunition. The legs 12 of the bipod are folded forwardly to provide a shoulder rest when the gun is carried.

We claim:

1. In a recoilless rifle, the combination of a barrel having an interrupted thread at its breech end, a nozzle having a thread at its forward end, a hinge coupling said nozzle to said barrel, a lock ring having its rearward end partially threaded onto said forward end of said nozzle and having on its forward end an interrupted thread adapted to cooperate with said interrupted thread of said barrel, said lock ring having a radial extension, means rotatably mounting a cocking shaft for movement With a control handle about the longitudinal axis of the shaft between predetermined limits, said cocking shaft extending transversely into said nozzle and having a groove at its inner end, said control handle having a recess engaging with said radial extension for rotating said ring in opposite directions between said predetermined limits to engage and disengage said interrupted threads, and latch means cooperating with said groove only during disengagement of said interrupted threads to lock said shaft and said handle against rotation.

2. In a recoilless rifle, the combination of a barrel having an interrupted thread at its breech end, a nozzle having a thread at its forward end, a hinge coupling said nozzle to said barrel, a lock ring having a radial inner surface partially threaded onto said forward end thread of said nozzle and having on a radial outer surface an interrupted thread adapted to cooperate with said interrupted thread of said barrel, said lock ring having an outwardly extending projection, means rotatably mounting a cocking shaft for movement with a control handle about the longitudinal axis of the shaft between predetermined limits, said cocking shaft extending transversely into said nozzle and having at its inner end a groove and means forming a cam surface, said shaft having a reduced section intermediate its ends and at one of its sides, said control handle having a recess engaging with said projec tion for rotating said ring in opposite directions between said predetermined limits to engage and disengage said interrupted threads, latch means cooperating with said groove only during disengagement of said interrupted threads to lock said shaft and said handle against rotation, a hammer encircling said shaft at said reduced section and resiliently biased thereagainst, and means cooperating with said cam surface to cock said hammer only upon the rotation of said shaft and said handle in a direction to engage said interrupted threads.

3. A combination according to claim 2 wherein said latch means includes a catch connected to a firing cable, and a sear movable by said cam surface upon rotation of said shaft to cock said hammer and engage said sear with said catch.

4. A combination according to claim 2 wherein said latch means is spring biased against a tang on a hinge block of said hinge.

5. A combination according to claim 3 wherein said shaft and hammer extend into said nozzle in directions perpendicular to one another and said sear and latch means are parallel with one another and extend into said nozzle at an angle with said shaft and said hammer.

Musser Apr. 10, 1956 Bluford Apr. 23, 1957 

1. IN A RECOILLESS RIFLE, THE COMBINATION OF A BARREL HAVING AN INTERRUPTED THREAD AT ITS BREECH END, A NOZZLE HAVING A THREAD AT ITS FORWARD END, A HINGE COUPLING SAID NOZZLE TO SAID BARREL, A LOCK RING HAVING ITS REARWARD END PARTIALLY THREADED ONTO SAID FORWARD END OF SAID NOZZLE AND HAVING ON ITS FORWARD END AN INTERRUPTED THREAD ADAPTED TO COOPERATE WITH SAID INTERRUPTED THREAD OF SAID BARREL, SAID LOCK RING HAVING A RADIAL EXTENSION, MEANS ROTATABLY MOUNTING A COCKING SHAFT FOR MOVEMENT WITH A CONTROL HANDLE ABOUT THE LONGITUDINAL AXIS OF THE SHAFT BETWEEN PREDETERMINED LIMITS, SAID COCKING SHAFT EXTENDING TRANSVERSELY INTO SAID NOZZLE AND HAVING A GROOVE AT ITS INNER END, SAID CONTROL HANDLE HAVING A RECESS ENGAGING WITH SAID RADIAL EXTENSION FOR ROTATING SAID RING IN OPPOSITE DIRECTIONSB BETWEEN SAID PREDETERMINED LIMITS TO ENGAGE AND DISENGAGE SAID INTERRUPTED THREADS, AND LATCH MEANS COOPERATING WITH SAID GROOVE ONLY DURING DISENGAGEMENT OF SAID INTERRUPTED THREADS TO LOCK SAID SHAFT AND SAID HANDLE AGAINST ROTATION. 